Process of treating cast ingots.



G. P, MoNIPP. I PROOESS 0F TREATING CAST INGOTS.

Patented Feb.'18, 1913.

APPLICATION mum Mia. 28. 1911.

FIG. 2

INVENTOR fiWw WITNESSES GILBERT P. McNIFF, 0F MUNHALL, PENNSYLVANIA.

PROCESS OF TREATING CAST INGOTS.

Specification of Letters Patent.

Patented Feb. 18, 1913.

Application filed August 28, 1911. Serial No. 646,509.

To all whom it may concern Be it known that I, GILBERT P.'M( NIFF, acitizen of the United States, residing at Munhall, in the county ofAllegheny, State of Pennsylvania. have invented a certain new and usefulProcess of Treating Cast ingots, of which the following is aspecification.

My invention relates to the manufacture of ingots and more particularlyrelates to the treatment of ingots after being teemed into the ingotmolds.

It has heretofore been proposed to insert a metal bar of approximatelythe same composition as the metal forming the ingot into its centerwhile the ingot is still molten, the bar becoming welded to the metal ofthe ingot in order to reduce the amountof piping and segregation. It hasalso been the practice to introduce aluminum, in the form of shot, intothe molds shortly after the commencement of the teeming operation. Ithas also been proposed to cover the top of the cast ingot with acarbonaceous material or a refractory non-conductor of heat or both todelay solidification of the ingot and thereby lessen piping andsegregation in the ingots.

One object of my invention is to provide a novel method of treatingingots after being teemed whereby occluded gases in the ingot aredissolved, the escape of such gases is facilitated and the formation ofblow holes thereby largely prevented and overcome.

Another object of the invention is to provide an improved process oftreating ingots after teeming by the use of which solidification of themetal is retarded to the end.

that piping and segregation are materially reduced and the production ofdense ingots which are uniformly solid s assured. A further objectofthis invention is in treating the teemed ingots by the series of novelsteps as more fully appears hereinafter.

Referring to the drawings forming part of this specification, Figure 1is a plan showing one form of apparatus adapted for use in carrying outthe steps of my improved method. Fig. 2 is a side elevation, partly insection, of the apparatus shown in Fig. 1.

In the drawings, the numerals 2, 2, designate mold cars having molds 3mounted on end" thereon in the usualmann'er, and suspended from atraveling crane or other suitable carrying mechanism in position forpouring or teeming is a pouring ladl l having a bottom pouring openingthrough which the molten metal is delivered into the molds in the usualknown manner.

Secured to the side of the ladle 4 is a bracket 5 having an arm 6adjustably held in position thereon, the arm being lengthwise adjustablein the bracket and being held in adjusted position by means of theclamping screw 7. Extending downwardly through a vertical opening in theend of the arm (3 is a lengthwise movable rod or bar of aluminum 8 whichis held in position and is manipulated by means of the lever or handle9, this lever having a U-shaped hook 10 which embraces the rod 8.

In carrying out my improved process of making ingots, the metalis teemedinto the molds 3 by any of the several known methods. aluminum in theform of shot being added while the ingots are being teemed in the usualmanner when found necessary or desirable.

After teeming each ingot, a layer of nonconducting material 11 isimmediately provided upon the still molten upper end of the ingot toform a blanket or cover so as to prevent chilling and delaysolidification of the top end of the ingot, coke dust or othercombustible non-conductor preferably being employed, as in addition tothe blanketing effect of such material the heat of combustion is addedthereto.

Ina short time after each mold 3 is filled, when'the metal of the ingotbegins to set, generally as soon as the filled mold and pouring ladle 4have been moved relatively a sufficient distance for the mold to clearthe ladle, a rod or bar of aluminum or other reducing metal 8 is thrustdownwardly through the coke-dust or other non-conducting material placedon top of the metal in the mold, into the center of the still moltenmetal in the ingot mold. The hook 10 on the end of the handle 9 is thenplaced to embrace and adjustably hold the rod 8 in place and tomanipulate the rod manually with the lower end of the rod projectingdownwardly into the molten'metal within the mold. H

The steel forming the ingot, which is still molten, is then stirred withthe rod of alu. minum or other reducing metal through the medium of thehandle 9 until the rod is melted or burned off, and another shorter rodis then employed to continue the stir-.

5 Instead of using the apparatus shown for manipulating the rods, theinsertion of the rods 8 and the stirring may be done entirely by hand,as in this way the operator can by the feel of the rod determine theamount of stirring necessary to afi'ord the desired result.

The rod preferably is extended downwardly to the bottom of the ingotalthough the distance will vary as changed conditions are presentedduring the treating operations.

.dIn the operation of my improved process,

with the apparatus shown, arod of aluminum is inserted in the mold, asis shown in the drawings, and the hook 10 on the handle"9 iscaused toengagethe upper end of the rod 8.- The handle is then moved manually bythe operator so as to cause the lower end of the bar 8 to rock'or rotatein a circular path and in this way stir the metal in the mold. The rodis lowered or permitted to descend in the mold from time to time as thelower end of the rod is melted, or burned ofi, and a new rod inserted toreplace the rod, as required.

The rod 8 being introduced into the ingot after the pouring operation iscompleted which 'is later in the ingot-forming operation than has beencontemplated in the methods of; introducing aluminum used heretofore andat a time when solidification of the ingot has commenced, muchmoreeflicient results are obtained owing to the lessened solubility of steelfor the gases and the oxide when the steel is solidifying.

Stirring the steel by means of a rod of aluminum aifords a greateropportunity for the metal in the ingot to settle solidly and alsopermits and causes the occluded aluminum or alumina to rise to thesurface. The exothermic reaction of aluminum to alumina addsconsiderable heat locally at all points in the length of the ingot'andany blow holes which have formed become filled with" the hotter metal,resulting from the exothermic reaction. 7

Continuing the stirring with "a rod or bar of aluminum after the firstbar has been melted or burned oft by contact with the molten steelreduces the extent of piping in the ingot by collecting the gases andoxids nearer the top of the ingot while, prolonglng the time the top ofthe ingot remains in I a molten condition permits the gases to escapeand assists in lessening the amount of se egation' i he advantagesof myinvention will be ap arent to those skilled in theart.

.' ipin-g and segregationin the ingot'will vbe reduced to a large extent"while thec'ost oftreating ingots in accordance with my invention willbe so small as to be practically negligible.

Modifications in the steps of the process and in the apparatus used in:carrying out my improved process may be made without departing from myinvention. Reducing metals other than aluminum may be employed informing the rods used in carrying out my improved process.

The apparatus for handling the aluminum rods may be secured to thepouring platform or other fixed support instead of to the ladle as shownand other changes may be made without departure from my invention asdefined-in the claims.

I claim 1. The process consists in covering of treating ingots which thetop of the teemed or rod of aluminum lengthwise into the cast ingots andstirring the molten metal in the mold therewith.

2. The process of treating ingots which consists in covering the topofthe teemed ingots with a ducting material ,,and then stirring themolten metal forming the ingot with a rod or barof aluminum until therod or bar is melted or burned off by contact with the metal of theingot.

3. The process of treating ingots which consists in pourin the metalinto a mold and thenintroducing a bar or rod of aluminum lengthwise intothe teemed ingot.

4:. The process of treatingingots which consists in teeming the metalinto a mold,

blanketing layer of non-con 1 inserting a rod or bar of aluminumlengthwise into the mold and then stirring the metal forming the top ofthe ingot with a rod or bar of aluminum while the metal is solidifyingand becoming set in the mold.

5. The process of treatlng ingots which consists in teeming the metalinto a mold, inserting a rod or bar of aluminum lengthwise into themold, then stirring the metal forming the top of the ingot with a rod orbar of aluminum while the metal is solidifying and becoming set in themold and then continuingthe stirring of the metal forming the top of theingot with another aluminum rod or bar until the metal of the ingot isfurther cooled and-solidified.

6. The process of treating ingots which consists in pouring the metalinto' a mold and then introducing a bar or rod formed of a reducingmetal lengthwise into, the teemed ingot.

8. The process of treating ingots which consist-sin teemin the metalinto a mold, inserting a rodor ar formed of a reducing metal lengthwiseinto the mold, then stirrin the metal forming the to of the ingot with arod or baj'r formed 0 a reducing metal while the metal is solidifyingand becoming set in the mold and then continuing the staining of themetal forming the top of my hand.

' GILBERT P. MoNIFF.

Witnesses:

JOHN -BELL, Jr., FRANK L. TOY,

